1. Field of the Invention
Aspects of the present invention relate to an electrode, a method of preparing the electrode, and an electronic device including the electrode, and more particularly, to an electrode including a metal oxide and a plurality of 12CaO.7Al2O3 particles, a method of preparing the electrode, an electronic device including the electrode, and specifically, an organic light emitting device including the electrode.
2. Description of the Related Art
Recently, demands have been increasing for transparent electrodes having low resistance, high degrees of optical transmittance, and low work functions for use in various electronic devices, specifically electronic devices related to emission of light. Examples of such specific electronic devices include organic light emitting devices (OLEDs). OLEDs are self-emitting, have higher brightness than liquid crystalline display devices, and can be thin because they do not use backlight units.
An OLED includes an anode, an organic layer, and a cathode that are sequentially stacked on a substrate in which a pixel circuit, such as a thin film transistor, is formed. OLEDs can be categorized into top-emission OLEDs and bottom-emission OLEDs. In a top-emission OLED, light is emitted in the direction opposite to the substrate on which the OLED is disposed, that is, light is emitted toward the cathode. Thus, top-emission OLEDs can have higher aperture ratios than bottom-emission OLEDs in which light is emitted toward the substrate. As a result, high light emission efficiency can be obtained in a top emission OLED. To achieve this, the cathode of the OLED should be transparent.
Such a transparent cathode can be formed of a transparent metal oxide, such as indium tin oxide (ITO). However, ITO has a limitation as a cathode material of an OLED because of its relatively high work function. The transparent cathode can also be formed of a metal alloy, such as MgAg. A metal alloy, such as MgAg, has low resistance and a low work function. However, even when the metal is a very thin film, for example, with a thickness of 15 nm, the optical transmittance in the visible spectrum is only about 30%. Therefore, conventional cathodes do not have ideal characteristics of sheet resistance, optical transmittance, or work function. Accordingly, there is a need to develop cathodes with improved characteristics of low sheet resistance, high optical transmittance and low work function.